Oncology for Scientists RPN 530

Fall 2015

Cancer Cell Metabolism

Gokul Das, Ph.D. Department of Pharmacology & Therapeutics Center for Genetics & Pharmacology (CGP)

Room 4-304 Tel: 845-8542

Email: gokul.das@roswellpark.org

Acquired Abilities for Cancer Progression: Cancer Hallmarks 2000 vs 2011

An Emerging Hallmark: Reprogramming Energy Metabolism

Hanahan D, Weinberg RA. Hallmarks of Cancer: The Next Generation. Cell 2011, 144:6462

Metabolism:  Collection of controlled intracellular biochemical reactions that convert nutrients and endogenous molecules to energy and matter (proteins, nucleic acids, and lipids) that sustain life

A sequence of chemical reactions, where the product of one reaction serves as a substrate for the next, is called a metabolic pathway or biochemical pathway  The set of reactions occurring within the cell are called intermediary metabolism or intermediate metabolism Most metabolic pathways take place in specific regions of the cell

Metabolism (Overview)

3

Map of Metabolic Pathways

4

Basic Chemical Reactions Underlying Metabolism

Catabolism and Anabolism

Two major classes of metabolic reactions  

Catabolic pathways  • Break larger molecules into smaller products  • Exergonic (release energy)  

Anabolic pathways  • Synthesize large molecules from the smaller

products of catabolism  • Endergonic (require more energy than they

release)5

Metabolism Composed of Catabolic and Anabolic Reactions

6

BioenergeticsCell Energy ATP is the main energy currency of cells

Formation of ATP Degradation of glucose and glycogen   -Glycolysis Oxidative formation of ATP   - Oxidative phosphorylation  Anaerobic pathways   - Do not involve O2   - Glycolysis

Aerobic pathways - Require O2   - Oxidative phosphorylation   7

8Hans Krebs, Nobel Prize in 1953; Science 2010, 330:1338

Kreb’s Cycle/TCA Cycle

Basic Steps Involved

Glycolysis

Krebs  Cycle

Electron  Transport  System

Acetyl  CoA  Formation

1

2

3

49

10

ATP Generating Metabolic Pathways

Glycolysis

Glycolysis (“splitting of sugar”) breaks down glucose into two molecules of pyruvate   Occurs in the cytoplasm and has two major phases  

– Energy investment phase  – Energy payoff phase  

Occurs whether or not O2 is present   Glycolysis harvests chemical energy by oxidizing glucose to pyruvic acid   The oxidation of glucose to pyruvic acid produces ATP and NADH  

Energy yield: 2 ATP and 2 NADH

Glucose Pyruvic acid

11

Balance Sheet for Glycolysis

Input

1 Glucose

2 ADP + Pi 2 NAD+

Output

2 Pyruvate

2 ATP

2 NADH

12

Transition  Reaction

13

Krebs  Cycle  (Citric  Acid  Cycle)

Transition  Reaction

14

Oxidative Phosphorylation

15

Overall ATP Production

Electron Transport System 34 Citric Acid Cycle 2 Glycolysis 2 SUBTOTAL 38 NADH Transport into Mitochondrion* -2 TOTAL 36

(-2) some ATP is used to pump NADH across membrane so ~ 36 ATP

The high-energy ATP molecules store 7.3 kcal of energy per mole16

Net  ATP  Yield

34 to 36 molecules ATP for every glucose molecule

about  40%  efficiency

ATP

17

The high-energy ATP molecules store 7.3 kcal of energy per mole

How is Cancer Cell Metabolism different ?

18Matthew  G.  Vander  Heiden,  Science  Webinar.

The Warburg Theory of Cancer or "Warburg hypothesis"

Dr.  Otto  H.  Warburg              (  1883  –    1970)

Warburg hypothesis 1924 “Cancer, above all other diseases, has countless secondary causes. But, even for cancer, there is only one prime cause. Summarized in a few words, the prime cause of cancer is the replacement of the respiration of oxygen in normal body cells by a fermentation of sugar… " -- Dr. Otto H. Warburg in Lecture  

On the Origin of Cancer Cells. Otto Warburg Science 24 February 1956: 309-314. 19

Observation that most cancer cells predominantly produce energy through a high

rate of glycolysis followed by lactic acid fermentation, rather than through oxidative

phosphorylation in the mitochondria

What is the Warburg Effect?

20

The uncontrolled growth and division of cancer cells relies not only on the deregulation of cell proliferation, but also on the reprogramming of

cellular metabolism, including increased aerobic glycolysis (known as the Warburg effect)

Acquired Abilities for Cancer Progression: Cancer Hallmarks 2000 vs 2011

An Emerging Hallmark: Reprogramming Energy Metabolism

Hanahan D, Weinberg RA. Hallmarks of Cancer: The Next Generation. Cell 2011, 144:64621

22

Glycolysis and Oxidative PhosphorylationM

atth

ew G

. Van

der H

eide

n et

al,

2009

. Sci

ence

, 324

:102

9-10

33

23

Mat

thew

G. V

ande

r Hei

den

et a

l, 20

09. S

cien

ce, 3

24:1

029-

1033

Warburg  Effect

QO2:  oxygen  consumed/ml  QM

O2:  lactic  acid  produced  aerobically  /ml  

QMN2:  lactic  acid  produced  anaerobically  /ml

Science  1956;124:  (3215)  269-­‐70

The  higher  the  malignancy,  the  greater  the  fermentation  and  the  smaller  the  respiration

24

Nature  Rev  Cancer    2004;4:891-­‐9Low  malignancy High  Malignancy

Higher Glucose Uptake Correlates With More Aggressive Phenotypes and Poorer Clinical Outcomes

25

26

• 18F-FDG: [18]F-flourodeoxyglucose (FDG) Imaging • 18F -FDG is a glucose analog with replacement of the oxygen in C-2 position with 18-

fluorine. Though it behaves as glucose in many situations, there are some important differences that should be understood.

• Uptake: Just as glucose, FDG is actively transported into the cell mediated by a group of structurally related glucose transport proteins (GLUT). Once intracellular, glucose and FDG are phosphorylated by hexokinase as the first step toward glycolysis. Normally, once phosphorylated glucose continues along the glycolytic pathway for energy production. FDG however cannot enter glycolysis and becomes effectively trapped intracellularly as FDG-6-Phosphate. Tumor cells display increased number of glucose transporters, particularly GLUT-1 and GLUT-3, as well as higher levels of hexokinase, isoforms type I and II. Tumor cells are highly metabolically active (high mitotic rates) ,and favor the more inefficient anaerobic pathway adding to the already increased glucose demands. These combined mechanisms allow for tumor cells to uptake and retain higher levels of FDG when compared to normal tissues.

• FDG is not cancer specific and will accumulate in areas with high levels of metabolism and glycolysis. Therefore increased uptake can be expected in sites of hyperactivity (muscular, nervous); active inflammation (infection, sarcoid, arthritis, etc.); tissue repair, etc.

Clinical FDG-PET Scanning Exploits Cancer Metabolism

27Matthew G. Vander Heiden et al, 2009. Science, 324:1029-1033

Clinical FDG-PET Scanning Exploits Cancer Metabolism

Cancer: Principles & Practice of Oncology 9th Edition

Cancer Cell Metabolism:Warburg and Beyond

28

The Possible Advantages of the Altered Metabolism of Cancer Cells

Altered  Metabolism  Provides  Substrates  for  Biosynthetic  Pathways  

         Aerobic  glycolysis  is  about  100  times  faster  than    oxidative-­‐              phosphorylation  in  the  mitochondria  

         Increased  glycolysis  allows  the  diversion  of  glycolytic  intermediates              into    various  biosynthetic  pathways  

           Facilitates  the  biosynthesis  of  the  macromolecules  and  organelles              required  for  assembling  new  cells  

         Ensures  that  cancer  cells  have  a  ready  supply  of  building  blocks  needed  for  macromolecule  synthesis  

29

Glucose and Glutamine Feed Cell Growth and Proliferation

Dang C V Genes Dev. 2012;26:877-890

Copyright © 2012 by Cold Spring Harbor Laboratory Press30

Most  of  the  Increased  Nutrient  Uptake  in  Cancer  is  Used  to  Support  Biosynthesis  

Matthew  G.  Vander  Heiden.  Nat  Rev  Drug  Discov.  2011   31

10%

Normal differentiated cells Oxidative Phosphorylation

CO2

Proliferating cells Aerobic Glycolysis

Pyruvate Kinase (PK-M2 ) Activity is Regulated by cell Growth Signals and Promotes Anabolic Metabolism

32

PKM2 Regulates an Anabolic Program to Support Cancer Cell Proliferation

33

The Possible Drivers of the Altered Metabolism of Cancer Cells

Hypotheses: Hypoxic conditions (A decrease in ambient O2 availability and levels)  

Persistent metabolism of glucose to lactate even in aerobic conditions is an adaptation to intermittent hypoxia in pre-malignant lesions  

Upregulation of glycolysis leads to microenvironmental acidosis requiring evolution to phenotypes resistant to acid-induced cell toxicity  

Subsequent cell populations with upregulated glycolysis and acid resistance have a powerful growth advantage, which promotes unconstrained proliferation and invasion

34

The tumor microenvironment selects for altered metabolism

Hypoxia-Inducible Transcription Factor (HIF)

Tumors outgrows the diffusion limits of its local blood supply, leading to hypoxia and stabilization of the hypoxia-inducible transcription factor, HIF

HIF-1 is critical to glycolysis, induces nearly all enzyme transcription

35

HIF-1 Pathway

Meijer T W et al. Clin Cancer Res 2012;18:5585-5594

©2012 by American Association for Cancer Research36

OXPHOS  In  

Mitochondria

OXPHOS-­‐  Oxidative  Phosphorylation37

Linking Oncogenes and Tumor Suppressor's to Tumor Cell Metabolism

38Cancer  Cell.  2008  Jun;13(6):472-­‐82

39

Cancer  Cell.  2008  Jun;13(6):472-­‐82

40

Science  2006;312:1650-­‐4 41

p53 and Mitochondrial Respiration

Shen L et al. Clin Cancer Res 2012;18:1561-1567©2012 by American Association for Cancer Research

42

P53 Regulates Cellular Metabolism

Reciprocity between Regulatory State and Metabolic State

• “If regulatory state (transcription factors, signaling pathways, etc.) is accepted to control metabolic state, is it not also unconditionally certain that metabolic state will reciprocally control the regulatory state itself? Understanding this reciprocity, and digging to the bottom of it, is where the future lies”.

Steve McKnight, Science 2010, 330:1138-39

43

44

a. IDH1 and IDH2 mutations are grouped together due to their mechanistic similarity and exclusive occurrence in the tumors. b. For studies with sample number less than 100, the actual numbers, instead of percentages of mutation are given. c. Glioma includes all WHOI-IV glioma. d.Includes central enchondromas and chondrosarcomas, periosteal chondromas, and cartilaginous tumors associated with Maffuci and Ollier syndrome. e. AML, acute myelogenous leukemia. f. All histological subtypes. g. HLRCC,  hereditary  leiomyoma  with  renal  cell  carcinoma. HLRCC, hereditary leiomyoma with renal cell caa. h. MCUL, multiple cutaneous and uterine leiomyoma. i. Mucinous histological subtype. j. GIST, gastrointestinal stromal tumor. k. Intrahepatic cholangiocarcinoma only, no mutations were found in extrahepatic cholangiocarcinoma. l. Angioimmunoblastic T-cell lymphoma confirmed by molecular signature (w/o confirmation rate was 20%). no mutations were found in other peripheral T-cell lymphomas.

Mutation of Metabolic Genes in Cancer

Oerman etal., 2012. Seinars Cell Dev Biol., 23:370-380

Mutation  of  8  metabolic  genes  in  cancer

Phosphoglycerate dehydrogenase is overexpressed in some cancers and catalyzes a growth-promoting metabolic pathway. Glycolytic cancer cells convert glucose into pyruvate, which can then be oxidized in the mitochondria or converted into lactate. Cells containing enhanced expression of the enzyme phosphoglycerate dehydrogenase (PHGDH), either as the result of genomic amplification of its gene on chromosome 1p12 or through other mechanisms, divert 3-phosphoglycerate (3-PG) away from glycolysis into the serine/glycine biosynthetic pathway (red arrows), which generates several important metabolic intermediates. Along this pathway, transamination of 3-phospho-hydroxypyruvate (3-POHpyr) by the enzyme phosphoserine aminotransferase-1 (PSAT1) generates α-ketoglutarate (α-KG), which can then be oxidized in the tricarboxylic acid (TCA) cycle. Serine and glycine are used to produce glutathione, proteins, nucleic acids, phospholipids, and sphingolipids, and other molecules required for cell growth and proliferation. Abbreviations: Ac-CoA, acetyl coenzyme A; Cit, citrate; Fum, fumarate; GSH, glutathione, Isocit, isocitrate; Mal, malate; OAA, oxaloacetate; Succ, succinate

Phosphoglycerate dehydrogenase (PHGDH): a TCA Cycle Enzyme Overexpressed in some Human Tumors

Andrew R. Mullen, Ralph J. DeBerardinis, 2012. Trends in Endocrinology & Metabolism, 23:552-559

Andrew R. Mullen, Ralph J. DeBerardinis, 2012. Trends in Endocrinology & Metabolism, 23:552-559

Mutant IDH1/2 enzymes produce an oncometabolite with pleiotropic effects on cell signaling and epigenetics. Normal cells contain wild-type isocitrate dehydrogenases IDH1 and IDH2 (gray). These enzymes catalyze the reversible conversion of isocitrate to α-ketoglutarate (α-KG), generating NADPH and CO2. α-KG can be oxidized in the TCA cycle or used as a cofactor by α-KG-dependent dioxygenase enzymes. Tumor cells with somatically-acquired, heterozygous active site mutations in IDH1 or IDH2 (mIDH1/2, green) display a neomorphic enzyme activity that reduces α-KG to R(–)-2-hydroxyglutarate [(R)-2HG], using NADPH as a cofactor. Owing to its structural similarity to α-KG, (R)-2HG modulates the function of α-KG-dependent dioxygenases, stimulating prolyl hydroxylase activity, and inhibiting several enzymes that regulate histone and DNA modifications. Together, these processes exert complex effects on gene expression that probably contribute to the malignancy of IDH1/2-mutant cells. Abbreviation: Succ, succinate.

Mutation in a TCA Cycle Enzyme Produces an “Oncometabolite”

(a) Succinate dehydrogenase (SDH) and fumarate hydratase (FH) are TCA cycle enzymes and tumor suppressors. In normal cells, succinate and fumarate are generated through oxidative metabolism of glutamine-derived α-ketoglutarate (α-KG) (gray arrows). Subsequent metabolism around the TCA cycle generates citrate for lipid synthesis. SDH and FH deficiency interrupt this pathway, with accumulation of succinate and fumarate, respectively. FH-deficient cells redirect TCA cycle metabolism in two ways (red arrows). First, the cells shunt succinyl-CoA into a pathway of heme biosynthesis and degradation, culminating in the secretion of bilirubin. Inhibiting heme oxygenase-1 (HMOX1) in this pathway selectively kills cells with FH deficiency. Second, to produce citrate, the cells use reductive carboxylation of glutamine-derived α-KG. IDH1 and/or IDH2 participate in this reaction, and subsequent metabolism of citrate produces acetyl-CoA for fatty acid/lipid synthesis, and other TCA cycle intermediates such as oxaloacetate and malate, which are normally produced downstream of FH. (b) Keap1 is an electrophile sensor. In the absence of fumarate and other electrophiles, Keap1 negatively regulates the transcription factor Nrf2, targeting it for degradation. In FH-deficient cells, cysteine residues on Keap1 are modified by fumarate-dependent succination, in which cysteine is converted to S-(2-succinyl)-cysteine. Nrf2, now active, can activate the transcription of genes involved in the antioxidant response. Abbreviations: Ac-CoA, acetyl coenzyme A; Cys, cysteine; HMOX1, heme oxygenase-1; IDH1/2, isocitrate dehydrogenase isoforms 1 and 2; OAA, oxaloacetate; Succ-CoA, succinyl coenzyme A.

Effects of mutation of TCA cycle enzymes on metabolism and gene expression

Andrew R. Mullen, Ralph J. DeBerardinis, 2012. Trends in Endocrinology & Metabolism, 23:552-559

Sayako Katada, Axel Imhof, Paolo Sassone-Corsi, 2012. Cell, 148:-24-28

Schematic representation of the histone H3 tail with residues that can be modified by various enzymes (E), leading to phosphorylation (P), acetylation (Ac), methylation (Me), ubiquitination (Ub), and glycosylation (Gly). These modifications have been associated with changes in chromatin organization, gene activation, silencing, and several other nuclear functions. Each enzyme utilizes cellular metabolites, whose availability would dictate the efficacy of the enzymatic reaction.

Chromatin-Remodeling Enzymes “Sense” Cellular Metabolism

Kroemer and Pouyssegur, 2008. Cancer Cell, 13:472-482

The Seven Hallmarks of Cancer and Their Links to Tumor Metabolism The hypothetical links between different metabolic alterations and the seven nonmetabolic characteristics of neoplasia (circle) are depicted. Centripetal arrows (pointing from the inside outwards) indicate how the seven hallmarks of cancer can impinge on metabolism. Centrifugal arrows (pointing from the outside inwards) illustrate how neoplasia-associated metabolic reprogramming can contribute to the acquisition of the seven hallmarks. Ang-2, angiopoietin-2; GLUT, glucose transporter; HIF, hypoxia-inducible factor; HK, hexokinase; OXPHOS, oxidative phosphorylation; PGM, phosphoglycerate mutase; PI3K, phosphatidylinositol 3-kinase; SCO2, synthesis of cytochrome c oxidase 2; VDAC, voltage-dependent anion channel; VEGF, vascular endothelial growth factor.

Summary: Factors Affecting Cancer Metabolism

TW Mak et al., Nat Rev Cancer, 2011 50

51

Diagram depicting clonal expansion of cancer cells after a hypothetical mutational event. (B) This cartoon illustrates the significantly different number of cell divisions needed to produce an adult elephant versus a mouse from similar-sized embryos. (C) Empirical measurements of specific metabolic rates (energy in watts per gram of tissue) reveal a power law relation with body mass (grams) as illustrated by a linear log–log relation (dashed line). Cartoons of the mouse and elephant are placed over the approximate body mass. Note the significant difference in specific metabolic rates (several orders of magnitude) between the mouse and elephant

Metabolism Contributes to Cancer

C.V. Dang, 2012. Genes & Development, 26: 877-890

The Possible Drivers, Advantages, and Potential Liabilities of the Altered Metabolism of Cancer Cells

Hsu PP et al. Cell. 2008 Sep 5;134(5):703-752

Drivers (A and B). The metabolic derangements in cancer cells may arise either from the selection of cells that have adapted to the tumor microenvironment or from aberrant signaling due to oncogene activation. The tumor microenvironment is spatially and temporally heterogeneous, containing regions of low oxygen and low pH (purple). Moreover, many canonical cancer-associated signaling pathways induce metabolic reprogramming. Target genes activated by hypoxiainduciblefactor (HIF) decrease the dependence of the cell on oxygen, whereas Ras, Myc, and Akt can also upregulate glucose consumption and glycolysis. Loss of p53 may also recapitulate the features of the Warburg effect, that is, the uncoupling of glycolysis from oxygen levels. Advantages (C–E). The altered metabolism of cancer cells is likely to imbue them with several proliferative and survival advantages, such as enabling cancer cells to execute the biosynthesis of macromolecules (C), to avoid apoptosis (D), and to engage in local metabolite-based paracrine and autocrine signaling (E). Potential Liabilities (F and G). This altered metabolism, however, may also confer several vulnerabilities on cancer cells. For example, an upregulated metabolism may result in the build up of toxic metabolites, including lactate and noncanonical nucleotides, which must be disposed of (F). Moreover, cancer cells may also exhibit a high energetic demand, for which they must either increase flux through normal ATP-generating processes, or else rely on an increased diversity of fuel sources (G).

53

Glycolytic Inhibitors With Anticancer Activity

Oncoene 2006; 25:4633-46 , J Bioegnerg Biomembr 2007; 39:267-74

54Oncogene  (2006)  25,  4633–4646,  J  Bioenerg  Biomembr.  2012  Feb;44(1):17-­‐29

Glycolytic Inhibitors With Anticancer Activity

55Kroemer and Pouyssegur, 2008. Cancer Cell, 13:472-482

Application and Integration of Tools to Study Tumor Metabolism

Cantor J R , and Sabatini D M Cancer Discovery 2012;2:881-898©2012 by American Association for Cancer Research

56

References

Recommended Reading: 1. Tumor cell metabolism: cancer's Achilles' heel. Kroemer G, Pouyssegur J.Cancer Cell.

2008 Jun;13(6):472-82. 2. Cancer cell metabolism: Warburg and beyond. Hsu PP, Sabatini DM.Cell. 2008 Sep

5;134(5):703-7 3. Understanding the Warburg effect: the metabolic requirements of cell proliferation.

Vander Heiden MG, Cantley LC, Thompson CB. Science. 2009 May 22;324(5930):1029-33.

4. On the origin of cancer cells. WARBURG O. Science. 1956 Feb 24;123(3191):309-14.57

Required Reading:  1. Understanding the Warburg effect. 2009. Science, 234:1029-1033.  2. Genetically-defined metabolic reprogramming in cancer cells. 2012. Trends in

Endocrinology and Metabolism, 23: 552-559.  3. p53 and metabolism. Vousden KH, Ryan KM. Nat Rev Cancer. 2009 Oct;9(10):

691-700  4. p53 regulates mitochondrial respiration. Matoba S, Kang JG, Patino WD, Wragg A,

Boehm M, Gavrilova O, Hurley PJ, Bunz F, Hwang PM. Science. 2006 Jun 16;312(5780):1650-3.  

5. Regulation of cancer cell metabolism. Cairns RA, Harris IS, Mak TW. Nat Rev Cancer. 2011 Feb;11(2):85-95